You don't have to shiver in the dark to reduce your home energy costs. Just ask the Luttrells and Wattays of Smyrna, Del.

For last month's Frugal Family Challenge, USA TODAY and Good Morning America Weekend challenged both families to cut their home energy bills. Steve Luxton, a home energy auditor for CMC Energy in Fort Washington, Pa., met with the families at the beginning of the month and offered energy-saving recommendations.

Both families cut their home energy bills by nearly a third, mostly by changing their habits. The Wattays won the challenge, but just by a couple of Btus. They reduced their monthly energy bill by 30.6%, while the Luttrells cut theirs by 29.4%. Here's a look at both families:

The Wattays

The Wattays' combined electricity and natural gas bills dropped by more than $150 in February from January. How they did it:

•Spent less time in the shower. Before the challenge, three of the Wattays' children, Benjamin, 14; Jessica, 12; and Cameron, 11, routinely took 30-minute showers. (Their fourth child, Spencer, is 6 months old.) By the end of the challenge, the children had reduced their shower time to seven minutes.

•Unplugged their space heater. Before the challenge, the Wattays often used a space heater to warm their family room, which has a 20-foot ceiling. At Luxton's suggestion, Dana, 44, installed a ceiling fan in that room. By rotating the fan in reverse, the Wattays were able to recirculate warm air that was trapped near the ceiling, making the space heater unnecessary.

•Lowered their thermostat. The Wattays' experience shows that lowering your thermostat just a couple of degrees can generate big savings. They programmed their thermostat at 67 degrees during the day — 2 degrees lower than they were used to — and set it to drop to 65 degrees at night. "It was a little cold at first, but I think we really got used to it," says Molly Wattay, 34.

The family also got in the habit of turning off lights and unplugging appliances that weren't in use. Because the changes they made were realistic, Molly believes they'll be able to maintain their energy-saving habits.

The Luttrells

The Luttrells cut their electricity and natural gas bills by $103, with most of the savings coming from lower electricity use. What they did:

•Unplugged their second refrigerator. Like a lot of families, the Luttrells have a second fridge in the basement for drinks. At Luxton's suggestion, they unplugged it. The family was surprised at the difference it made in their energy bill, says Jeanette, 36. Plus, she adds, "We really haven't missed it."

•Shortened their showers. Like the Wattay children, the Luttrell kids — Jessica, 10, and Julia, 8 — liked 30-minute showers. At the start of the challenge, the girls reduced their showers to as little as five minutes. "I don't even know if they got clean," Jeanette says. Toward the end of the month, they were still coming in at 10 minutes or less, she says.

•Lowered their thermostat. Initially, they turned it down to 67, but Jeanette says that was uncomfortable. Now, they're keeping it at between 69 and 70, and turn the heat down to 66 at night.

•Turned off unused appliances. The girls got in the habit of turning off their PlayStation when they were done, and the family shuts off their computer when it's not in use. It takes a few minutes to restart, Jeanette says, but it's not a big deal.

The Luttrells and Wattays proved you don't have to spend a lot of money on home improvements to make a big dent in home energy bills, Luxton says. "You can save energy, and sometimes it's right at the tip of your fingers."

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